Traditional active devices used in analog circuits are typically three-terminal devices that can rely on bipolar junctions or voltage field effects. Semiconductor and thermionic devices typically have one terminal in common with both the input and the output. For example, field effect transistor (FET) circuit topologies are often characterized as being common-source, common-gate, or common-drain. Bipolar topologies are often characterized as common-emitter, common-base, and common collector. Vacuum tube circuits can be common-cathode, common-grid (grounded base), or common-anode (grounded plate).
These conventional active devices may also have characteristics that limit their performance. For example, these devices may have significant coupling capacitance between the input and the output, such as due to the Miller effect. This capacitance may limit switching speed and bandwidth of these devices, such as when used in analog power amplifiers. The power added efficiency of these amplifiers may be limited by transistor characteristics. Also, these devices have 1/f noise, which may impact noise figure of these devices. Furthermore, when multiple ones of these devices are placed in close proximity, circuit design complexity may be increased in an effort to avoid latch-up conditions.
In addition, these active devices are fabricated with multiple types of distinct structures. For example, bipolar junction transistors and metal-oxide semiconductor FETs (MOSFETs) may be fabricated as n/p type devices. Because these active devices are typically three-terminal devices, for a particular type of device structure, current flows in a well-defined direction when the device is “on”. To support circuit building blocks that include complementary pairs of these devices, such as “push-pull” circuits, one or more devices of each type, such as n-type MOSFETs, are coupled to one or more devices of the other type, such as p-type MOSFETs. It would be desirable to be able to support these circuit building blocks with a device that is sufficiently flexible to do so with a single type of structure.
Moreover, analog circuits including these active devices may be fabricated using complementary MOS (CMOS) processes with upwards of twelve layers, which adds to both cost and size of these analog circuits.
It is against this background that a need arose to develop the magnetic logic units configured as analog circuit building blocks and related methods described herein.